Later, I can across a blue batik that matched the patches of blue that were among some of the blocks. But I did not know how to cut and sew them in. After being inspired by Wanda's finish, just last week, it dawned on me that the edges were just two triangles that I had cut using a template, minus the center seam allowance. I took the template out and traced it on template plastic. I cut a sample diamond, marked the 1/4" seam allowance on two edges, dropped a pin where they met and matched it to the inside seam of the quilt edge. I realized that I did not need to cut the whole diamond, but just beyond the halfway point so I could trim it after.
I sewed on the 1/4" line, when I got to the intersection, I just pivoted the fabric, easing it with a stiletto, and sewed to the outside edge. It was perfect (that does not happen too often). I continued to cut and mark all the side diamonds and sew them in. It was not that difficult. Why did it take so long for it to dawn on me?
After trimming the side diamonds flush, I added a blue strip along the side and a wider one at the top. It is exactly what I was thinking. How about that? Of course it took months to think of it.